000 AXNT20 KNHC 280537 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SUN APR 28 2013 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0500 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS THE COAST OF SIERRA LEONE AT 8N13W 5N16W TO 3N21W. THE ITCZ BEGINS AT 3N21W AND CONTINUES ALONG 3N30W EQ40W 1S44W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-7N BETWEEN 18W-29W. SIMILAR CONVECTION IS FROM 4S-EQ BETWEEN 18W-42W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGING CONTINUES TO COVER THE GULF OF MEXICO SUPPORTING SURFACE RIDGING EXTENDING FROM A 1030 MB HIGH NEAR 41N70W. THIS PATTERN IS PROVIDING EAST TO SOUTHEAST SURFACE FLOW OF 5-20 KT N OF 21N WITH THE STRONGEST WINDS MAINLY LOCATED S 24N. DRY AIR ALOFT IS PROVIDING CLEAR SKIES OVER THE CENTRAL...SOUTHERN AND EASTERN GULF. BROKEN TO OVERCAST SKIES COVER THE NW GULF N OF 24N W OF 91W DUE TO A FRONTAL SYSTEM AFFECTING SOUTHERN TEXAS. RADAR IMAGERY SHOW NUMEROUS STRONG CONVECTION AND THUNDERSTORMS FROM HOUSTON TO CORPUS CHRISTI AND EXTENDING ABOUT 60 NM OFF THE TEXAS COASTLINE. OVER THE NE GULF A WEAK SURFACE INVERTED TROUGH EXTENDS ALONG 30N84W TO 26N83W WITH NO SHOWERS ASSOCIATED TO IT. ANOTHER SURFACE TROUGH IS COMING OFF THE YUCATAN PENINSULA INTO THE SOUTHERN GULF EXTENDING FROM 21N89W 19N90W TO 17N92W. NO SHOWERS ACTIVITY HAS BEEN REPORTED/OBSERVED ASSOCIATED TO THIS SECOND TROUGH. OVER THE COURSE OF 24 HOURS...THE FRONT WILL LIKELY EXTEND A TROUGH INTO THE NW GULF THUS ENHANCING RAINSHOWERS/THUNDERSTORMS ALONG THE NORTHERN GULF COAST. CARIBBEAN SEA... THE BROAD UPPER RIDGE ACROSS THE GULF OF MEXICO CONTINUES INTO THE WESTERN CARIBBEAN WHILE BROAD UPPER TROUGHING COVERS THE REMAINDER OF THE BASIN WITH AXIS NEAR 73W. MOSTLY DRY AIR ALOFT IS PROVIDING FAIR SURFACE WEATHER CONDITIONS WITH CLEAR SKIES EXCEPT FOR A FEW PATCHES OF CLOUDS AND POSSIBLE SHOWERS SOUTH OF CUBA...PUERTO RICO AND THE MONA PASSAGE. A FEW PATCHES OF CLOUDS ARE ALSO MOVING THROUGH THE NW CARIBBEAN TOWARDS THE YUCATAN PENINSULA. A LARGE AREA OF RAINSHOWERS REMAINS EAST OF WINDWARD ISLANDS. MODEL GUIDANCE CONTINUES TO SHOW A GRADUAL SHIFT WEST OF THIS MOISTURE WITHIN THE NEXT 24 HOURS WHICH MAY BRING HEAVY SHOWERS AND THUNDERSTORMS TO THE SE CARIBBEAN. TRADEWIND FLOW OF 10-15 KT IS CURRENTLY PRESENT ACROSS THE MAJORITY OF THE BASIN WITH WINDS UP TO 20 KT ALONG THE COAST OF COLOMBIA. ATLANTIC OCEAN... UPPER LEVEL RIDGING OVER THE SE CONUS SUPPORTS SURFACE RIDGING ACROSS THE WEST ATLC ANCHORED BY A 1030 MB HIGH NEAR 41N70W. A NARROW UPPER LEVEL TROUGH TO THE EAST ALONG 64W SUPPORTS A COLD FRONT NORTH OF THE AREA WHICH TRANSITIONS INTO A SURFACE TROUGH ALONG 31N63W 26N65W. IN THE UPPER LEVELS...A WEAK SHORTWAVE TROUGH WITH AXIS NEAR 55W SUPPORTS A SECOND SURFACE TROUGH ALONG 28N58W 25N56W 23N53W WITH POSSIBLE ISOLATED SHOWERS WITHIN 150 NM EAST OF THE AXIS. A LARGE AREA OF SHOWERS/POSSIBLE THUNDERSTORMS ARE EAST OF THE WINDWARD ISLANDS FROM 6N-13N BETWEEN 50W-60W. THE ACTIVITY IS LIKELY LINKED TO MOIST SOUTHWESTERLY FLOW ALOFT AROUND THE WESTERN PERIPHERY OF A BROAD UPPER RIDGE ANCHORED BY A HIGH N OF THE BRAZILIAN COAST NEAR 7N37W. FARTHER NORTH...AN UPPER LEVEL LOW NEAR 37N40W CONTINUES TO SUPPORT 1006 MB SURFACE LOW NEAR 35N38W. A SURFACE TROUGH ASSOCIATED TO THAT LOW EXTENDS INTO THE DISCUSSION AREA ALONG 30N25W TO 26N26W. POSSIBLE ISOLATED SHOWERS ARE ALONG THE AXIS. A BROAD UPPER RIDGE COVERS THE REMAINDER OF THE EASTERN TROPICAL ATLC PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE AREA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ RAMOS